This invention relates to a computer system including a plurality of data storage systems and computers, and more particularly to data migration in a virtualized environment, where a data storage system is virtualized.
Computers store data in the data storage system. When a retention period of the data is longer than the life of the data storage system, it is required to migrate the data stored in an old data storage system to a new storage system before the device reaches its life. Upon the data migration, it is desirable that an unavailable time period be as short as possible, in which the computer cannot use the storage system, and furthermore, migration be conducted without any interruption.
As for a technique to migrate data from an old data storage system to a new one, for example, JP 10-508967 A and JP 2004-220450 A are disclosed. According to JP 10-508967 A and JP 2004-220450 A, before the start of data migration from an old data storage system to a new one, the computer is once disconnected and reconnected to a new data storage system.
Moreover, according to JP 2004-220450 A, in the new data storage system, a virtualized device (data storage area) corresponding to the device in the old data storage system is provided. By accessing to the virtualized device, the computer can access the device in the old data storage system corresponding to the virtualized device.